The In node is somewhat of a hybrid between a Join and a Filter node, in that it allows you to combine data from two inputs based on matching records in a chosen field; however, the In node will only return accompanying fields from one of those inputs. This is best illustrated by way of example.
For instance, suppose you had the following two datasets:
id |
measure |
---|---|
01 |
100 |
02 |
200 |
03 |
300 |
04 |
400 |
05 |
500 |
Input 1
id |
measure |
---|---|
01 |
1000 |
03 |
3000 |
05 |
5000 |
Input 2
There are two potential ways these datasets can be fed into an In node, and, thus, two potential outcomes. In either case, if id is specified as the Outer Source Field, then only matching records from the id field will be returned. Which records are returned within the measure field, however, will depend upon which input is specified as the "Outer Source."